It is a long time since the DVD (digital versatile disc) appeared as a random-access and removable recording medium. In recent years, a disk-shaped recording medium larger in capacity and more convenient to carry than DVD has been under development.
A DVD-Video has been laid down as a standard for recording video contents in DVD. According to DVD-Video, the DVD player in disk reproduction operation can assume various states. In DVD-Video, the state that can be assumed by the DVD player are classified into five types of what is called domains, and a model in which transition is made between the domains according to various conditions is used in the DVD player. Specifically, the DVD domains can be regarded as state variables having five possible values. The DVD player monitors the state variables to grasp the type of the contents being read from the disk.
The following five types of domains are defined in DVD-Video:
(1) First play domain (FP_DOM)
(2) Video manager menu domain (VMGM_DOM)
(3) Video title set menu domain (VTSM_DOM)
(4) Title domain (TT_DOM)
(5) Stop state
Incidentally, the stop state in (5) is not the domain in real terms.
The first play domain in (1) is defined as the first section of the disk and the preparatory state for reproduction in the DVD player. No-reproduction command is considered valid. The video manager menu domain in (2) is defined as the main menu on the whole disk or the whole disk surface and indicative of the display of the title menu. The command related to the menu is considered valid. The video title set menu domain in (3) is defined as the menu or the submenu (sub-picture, language, audio or angle) of the title or the title group and indicative of the root menu or submenu. The title domain in (4) is defined as the video contents in the title and the reproduction command is considered valid. The stop state in (5) is defined as the state in which the head has left the position for disk reproduction and returned to the original position, and the reproduction command is considered valid.
The navigation command for controlling the operation of the DVD player is limited by the domain used for the current state. The SELECT BUTTON command for selecting a predetermined item from the menu, for example, is significant as long as the menu is displayed. Specifically, the SELECT BUTTON command is significant in either state of the video manager menu domain of (2) or the video title set menu domain of (3). The FAST FEED command designating the video reproduction higher in speed than the normal unity speed, for example, is not significant as long as the player is stationary or the menu screen configured with a still image is on display. In other words, the FAST FEED command is significant in the title domain.
These domains of DVD-Video are described in, for example, “Jim Taylor: New Book on DVD Anatomy, 1st edition, Nexus Intercom Ltd., Jun. 7, 2003, p. 271” (Non-Patent Document 1).
The conventional DVD-Video described above has many domain types and detailed conditions for state transition between the domains, thereby posing the problem that it cannot be easily mounted on the DVD player.
Another problem is that unless the transition between the domains is fully understood, the disk production is impossible and it is difficult for the content producer to produce the disk. Specifically, due to the many domain types and the detailed conditions for transition between the domains, the transition between domains cannot be fully grasped. This imposes a heavy burden on the producer in producing the disk of a complicated configuration.
Further, the domain name and the actual operating method are not always coincident with each other, and therefore, the necessity of the significance of existence of the domains is small. This poses the problem that the many domain types, coupled with the detailed conditions for transition between the domains, constitute a factor for increasing the burden of disk production on the part of the producer.
In the DVD-Video, for example, as described above, the title domain and two types of menu domains (the video manager menu domain and the video title set menu domain) are defined. Originally, the main content (such as the original story of the movie) recorded in DVD should be reproduced in the title domain. Actually, however, the reproduction of the original story of the movie in the menu domain poses no problem. Although commands are different for transition between domains, however, the player operation is not different between the menu domain and the title domain after state transition to these domains. This is by reason of the fact that both the menu reproduction in the menu domain and the reproduction of the original story of the movie in the title domain are realized by a common logic structure called PGC (program chain) with the content data and the related reproduction control program combined.
This poses the problem that the otherwise free content production is restricted. Specifically, the determination of a given content as a menu or a title somewhat depends on the subjective viewpoint of the disk producer. Assuming that in the case where the original story of the currently reproduced movie has branches, for example, the contents employing the interactiveness is conceived by displaying the select button to select any one of the branches. In this case, the method using the conventional DVD-Video is ambiguous as to which, the menu domain or the title domain, is to be used for reproducing the contents displayed by the select button. In the case where it is desired to prepare, after the particular content, a content having interactiveness, for example, the state transition is hard to predict and the operation is liable to be difficult to verify.